Magnetoencephalography (MEG), the measurement of magnetic fields generated by electric currents in the brain, promises to be a safe, sensitive, non-invasive procedure for the measurement and localization of normal and pathological brain function. The main objective of this proposal is to develop and implemnt better source localization algorithms. Single current dipole localization procedures will be extended and validated. An interactive graphical display will be developed which will combine dipole fit, time series, magnetic field distribution and head shape data. A source localization software tools library will be designed. During Phase II, the library will be implemented and MEG data will be combined with structural images from MRI and/or CT. This project has the potential for significantly improving existing source localization software. The results will find application in the functional study of the normal brain, improved localization of epileptic foci and other neurological disorders, neuropharm- acological studies, and in the development of new sensor technology for neuromagnetometry.